Thermostatic switch



jan. 27, s. HEALEY $435,004

THERMO-STATI@ SWITCH Filed 5, 1944 lINVEN TOR.

afm/C196 A fran/vf r Patented Jan. 27., 1948 Sidney Healey, Y mesne assignments,

Washington, D. C., assignor, by

American Instrument Co., Inc., a corporation of Maryland Application May 5, 1944, Serial No. 534,329 4 claims. (Cl. 20o- 138) My invention relates broadly to thermostatic regulators and more particularly to an improved construction for increasing the efficiency and accuracy of thermostatic regulators.

One of the objects of my invention is to provide a construction of thermostatic regulator having means for minimizing losses by heat exchange between adjacent surfaces through which the thermostatic regulator may be installed.

Still another object of my invention is to provide a construction of thermostatic regulator in which losses due to detrimental action resulting from electroiytic deterioration of the thermosensitive element in a thermoregulator may be minimized.

Still another object of my invention is to provide a construction of thermoregulator having for'supporting the thermosensiimproving the efficiency of the improved Ameans tive .element for regulator,

Other and further objects of my invention reside in an improved construction of thermoregulator as set forth more fully inthe speciiication hereinafter' following by reference to the accompanying drawings in which:

Figure 1 is a side elevational view of the ther.- moregulator of my invention with parts broken away to show the securing means interconnecting the heat insulation supporting tube and the thermosensitive element; Fig. 2 is a top plan view of the thermo-regulator; Fig. 3 is an enlarged fragmentary longitudinal sectional view through the securing means interconnecting the thermosensitive element and the supporting means; Fig. 4 is a transverse sectional view taken on line 4-4 oi Fig. 3; Fig. 5 is a side view of the slidable sleeve-like securing means of my invention; and Fig. 6 is -a vertical sectional view through the sleeve-like securing means of my invention.

It has been the usual practice in thermoregulators to employ a metalli/c tube which extends from the main frame of the regulator and provides a supporting means for a helical bimetallic element constituting the thermoregulator. It has been customary to connect such helical bimetallic element to the supporting tube by machined screws. l have found that this point of connection and support is subject to deterioration as a result of electrolytic action brought about by the chemical action of gases and fluids adjacent which the thermoregulator must function and the differences in the electrochemical series of the metals constituting the bimetallic element, the material of the securing screws and the material of the supporting tube.A Moreover, the metallic supporting tube provides a good conductor for heat and cold-so that undesirable heat exchange is effected between the interior and exterior surfaces of any cabinet structure `or apparatus with which such thermoregulator is associated.

My invention-is directed to means which eliminates all of these disadvantages. I employ a supporting tube for a bimetallic element which is formed from heat insulation material which is a substantially non-conductor of heat or cold, thus eliminating heat' exchange losses in various installations of the regulator. I form the helical bimetailic element at one end with instruck projections which are arranged to enter aligned recesses in the supporting tube, I provide a resilient sleeve-like member internally grooved to flt over the end of the helical bimetailic element and over the supporting tube of insulation material for securing by wedge action the bimetallic element with respect to the supporting tube. The resilient sleeve-like member is formed from material of substantially the same electrochemical series as the material of the bimetallic element whereby detrimental electrolytic action is avoided. Thus a construction of thermoregulator is provided which may be produced on a quantity production basis inexpensively and'which will have very substantially useful life.

Referring to the drawings in detail reference character I represents the frame structure for the thermoregulator from which extends the central tubular support 2. The casing for the thermoregulator is represented at 3 carried by frame I. The adjustable contacts for the regulator are represented generally at 4 and 5 which are adjustable from the exterior of the casing of the thermoregulator by control of adjusting knobs 6 and l. Binding posts 8 and 9 carried by casing 3 connect through spring members represented at Il) and II with the adjusting screws which are provided for adjusting contacts 4 and 5. Binding post I2 carried by casing 3 serves as a terminal member for the helical spring I4 which connects to the contact supporting strip shown at I5. Contact supporting strip I5 is supported by insulated member I6 which is carried on the end of rod member I1 which projects through the tubular support 2 to the end of the bimetallic thermosensitive member represented at I8. The end of the helical bimetallic thermosensitive member IB is riveted as represented at I9 to the end of the rod member Il and at the opposite end is secured in accordance with my invention to the heaty insulated tubular support 20. TheV heat insulated tubular support is formed from heat insulation material substantially non-conductive to neat or cold. The tubular support 2li is mounted in the internally recessed socket portion 2I ot the tubular support 2. Set screws 22 pass through tubular support 2 and bear against the end of the heat insulated tubular support 20 securing the heat insulated tubular support 20 in position. The opposite end of the heat insulated tubular support is cut on a bias represented at 23 substantially conforming with the helical disposition of the convolutions of the bimetallic member I8. The end of the bimetallic member I8 is forced over the end of the tubular support 20. The tubular support 20 has a pair of recesses 24 formed therein at distances spaced apart substantially less than the width of the helical bimetallic member I8. The end of the blmetallic member I8 contains a pair of instruck projections 25 which are spaced to conform with the spacing of the recesses 24 and serve to key or interlock the helical bimetallic' member I8 with the end of the tubular support 20. In order tov maintain the helical -bimetallic member I8 in position with respect to the end of tubular support 28 I arrange resilient sleeve member 26 of such size and shape that will t over the end of tubular support 20 and clamp the end of the helical bimetaldc member I8 'with respect to the cylindrical wall oi' tubular support 20. The sleeve-like member 28 is internally recessed as represented at 21 to allow forthe thickness of the helical bimetalllc member I8 beyond-the external diameter of tubular support 20. As sleeve-like member 26 is forced downwardly over the end of tubular support 20 the lugs 25 and bimetallic member I8 are forced into the recesses 24 in tubular support 20 forming interlocking engagement between bimetallic member I8 and the tubular support 20. Sleevelike member 28 is longitudinally slotted as represented at 28 to insure resiliency and yieldability so that the sleeve-like member 26 serves as a clamping device. The extremity of sleeve-like member 26 is formed on a .bias represented at 29 conforming with the helical contour of the convolutions of the bimetallic member I8.

The contact supporting strip I5 carries contact elements 3i) and 3I which establish connection with either of the adjustable contacts 4 and 5. A set screw' 32 is provided for selectively setting the thermoregulator in any position to which it may be adjusted. Indicator 33 coacting with an appropriate scale 34 is used to determine the adjustment of the device,

A protecting tube 35 may be secured over the helical thermosensitive element I8 and maintained in position with respect thereto by connection with the depending tubular support 2. With this in view the external diameter of sleevelike member 26 is maintained at a minimum to fit in spacial relation to the internal diameter oi' the protecting tube 35.

While I have described my invention in one of its preferred embodiments I realize that modiiications may be made and I desire it to be understood that no limitations upon my invention are intended other than are imposed by the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is as follows:

1. A thermoregulator comprising in combination with a. frame structure a contact system mounted within said frame structure, a rod-like actuator extending through said frame structure for controlling said contact system, a tubular 4 member oi' thermal insulation material carried by said frame structure and surroamding said rodlike actuator, a thermosensitive element having helically arranged convolutions, said convolutions being connected at one end to said rod-like actuator and a pair of instruck projections carried by the other end oi' said thermosensitive element and extending into a pair o! coacting aligned recesses in said tubular member and a sleeve-like member longitudinally slidable over said therm0sensitive element and said tubular member for pressing said instruck projections into interlocking engagement with the coacting recesses in said tubular member.

2. A thermoregulator comprising in combination with a i'rame structure a contact system mounted within said frame structure, a rod-like actuator extending through said frame structure for controlling said contact system, a tubular member of thermal insulation material carried ing helically arranged convolutions, said thermosensitive element being connected at one end with said rod-like actuator, an instruck projection carried by the opposite end of said thermosensitive element and extending into said tubular member, and a sleeve-like member formed from resilient 3. A thermoregulator comprising in combination with a frame structure a contact system mounted within said frame structure, a rod-like extending through said frame structure said thermosensitive element extending into interlocking engagement with an aligned recess in said tubular member and a sleeve-like member slidable over and engageable with said tubular member, said sleeve-like member having an annularly recessed cylindrical oiset portion engageable over the end convolution of the last mentioned end of said thermosensitive element for clamping said thermosensitive element with respect to said tubular member and interlocking the instruck projection thereon with the aligned recess in said tubular member.

4. A thermoregulator comprisingin combination with a frame structure a contact system mounted within said frame structure, a rod-like actuator extending through said frame structure for controlling said contact system, a tubular member oi' thermal insulation material carried by said frame structure and surrounding said rod-like actuator, a thermosensitive element having helically arranged convolutions, said convolutions being connected at one end to said rodiike actuator, an instruck rounded projection on said thermosensitive element at the opposite end thereof adapted to engage in an aligned socket recess in said tubular member and a yleldable sleeve-like member having one edge formed on a bias substantially corresponding with the pitch of the helcally arranged convolutions of said thermosenstve element and slidable over said tubular member and the end convolution of said thermosensitive element for interlocking the instruck projection adjacent the end convolution of said thermosenstive element with said tubular member.

SIDNEY HEALEY.

REFERENCES CITED The Yfollowing references are of record in the le of this patent:

UNITED STATES PATENTS Number l Number Name Date Geisler Oct. 18, 1932 Appelberg Jan. 17, 1933 Post Dec. 12, 1933 Matthews May 12, 1942 De Lancey Nov. 17, 1942 Peteler Aug..29, 1933 Peteler Dec. 8, 1936 Nodine 1 Feb, 14, 1933 FOREIGN PATENTS Country Date Switzerland Mar. 1, 1932 

